Carl F. Falk
@cffalk.bsky.social
Associate Professor | Quantitative Psychologist | Psychometrician
https://www.psych.mcgill.ca/perpg/fac/falk/
https://scholar.google.com/citations?user=9BA_cL0AAAAJ
https://www.psych.mcgill.ca/perpg/fac/falk/
https://scholar.google.com/citations?user=9BA_cL0AAAAJ
Pinned
Carl F. Falk
@cffalk.bsky.social
· Jul 28
If you do survey research with Likert-type items and worry about random responders, Michael John Ilagan & I made a Shiny app we think some of you may like.
falkcarl.shinyapps.io/BotApp1/
#SurveyResearch #DataQuality #Psychometrics #OnlineSurveys #SurveyBots #RandomResponders #rstats #Shiny
falkcarl.shinyapps.io/BotApp1/
#SurveyResearch #DataQuality #Psychometrics #OnlineSurveys #SurveyBots #RandomResponders #rstats #Shiny
Question: what journal(s) might be a good home for a replication of a Monte Carlo simulation study in quantitative psychology? The study replicates fine; part of the purpose was just to show how to do it R (original was in SAS a long while ago).
#quantitativepsychology #rstats #replication
#quantitativepsychology #rstats #replication
September 30, 2026 at 4:36 PM
Question: what journal(s) might be a good home for a replication of a Monte Carlo simulation study in quantitative psychology? The study replicates fine; part of the purpose was just to show how to do it R (original was in SAS a long while ago).
#quantitativepsychology #rstats #replication
#quantitativepsychology #rstats #replication
Reposted by Carl F. Falk
NCME, alongside the Psychometric Society, is proud to announce a new resource: the International List of Graduate Programs in Psychometrics and Educational Measurement!
👉️ buff.ly/vwhnFWF
👉️ buff.ly/vwhnFWF
August 26, 2026 at 7:21 PM
NCME, alongside the Psychometric Society, is proud to announce a new resource: the International List of Graduate Programs in Psychometrics and Educational Measurement!
👉️ buff.ly/vwhnFWF
👉️ buff.ly/vwhnFWF
Reposted by Carl F. Falk
Have you seen MATILDA (matilda.fss.uu.nl)? Which stands for Measurement, Analysis & Theory for Intensive Longitudinal Data. MATILDA is a website with educational articles that help researchers align theory, measurement, and analysis when studying processes using intensive longitudinal data.
MATILDA
matilda.fss.uu.nl
June 17, 2026 at 7:15 AM
Have you seen MATILDA (matilda.fss.uu.nl)? Which stands for Measurement, Analysis & Theory for Intensive Longitudinal Data. MATILDA is a website with educational articles that help researchers align theory, measurement, and analysis when studying processes using intensive longitudinal data.
For detecting careless respondents, if interested in learning how several univariate cutoffs for outlier statistics (e.g., Mahalanobis distance, person-total correlation) can do, Michael Ilagan, Wenshuo Li and I also developed an #rshiny app to teach about this.
falkcarl.shinyapps.io/BotApp2/
falkcarl.shinyapps.io/BotApp2/
June 11, 2026 at 12:12 PM
For detecting careless respondents, if interested in learning how several univariate cutoffs for outlier statistics (e.g., Mahalanobis distance, person-total correlation) can do, Michael Ilagan, Wenshuo Li and I also developed an #rshiny app to teach about this.
falkcarl.shinyapps.io/BotApp2/
falkcarl.shinyapps.io/BotApp2/
Lab website redone with #quarto: www.psych.mcgill.ca/perpg/fac/fa...
The new one should make blog posts or tutorials easier.
Includes new sections on software 💻 and selected teaching resources 🏫.
News is temporarily disabled, but I hope to have it back up and running soon.
The new one should make blog posts or tutorials easier.
Includes new sections on software 💻 and selected teaching resources 🏫.
News is temporarily disabled, but I hope to have it back up and running soon.
www.psych.mcgill.ca
June 8, 2026 at 1:12 PM
Lab website redone with #quarto: www.psych.mcgill.ca/perpg/fac/fa...
The new one should make blog posts or tutorials easier.
Includes new sections on software 💻 and selected teaching resources 🏫.
News is temporarily disabled, but I hope to have it back up and running soon.
The new one should make blog posts or tutorials easier.
Includes new sections on software 💻 and selected teaching resources 🏫.
News is temporarily disabled, but I hope to have it back up and running soon.
Reposted by Carl F. Falk
I'm back with the biggest release of quarto-revealjs-editable to date 🙌
You no longer have to add .editable to anything, now you just click the Modify button, click on the element you want to move/edit and it becomes editable.
emilhvitfeldt.com/post/quarto-...
#quarto #slidecrafing
You no longer have to add .editable to anything, now you just click the Modify button, click on the element you want to move/edit and it becomes editable.
emilhvitfeldt.com/post/quarto-...
#quarto #slidecrafing
May 27, 2026 at 4:23 PM
I'm back with the biggest release of quarto-revealjs-editable to date 🙌
You no longer have to add .editable to anything, now you just click the Modify button, click on the element you want to move/edit and it becomes editable.
emilhvitfeldt.com/post/quarto-...
#quarto #slidecrafing
You no longer have to add .editable to anything, now you just click the Modify button, click on the element you want to move/edit and it becomes editable.
emilhvitfeldt.com/post/quarto-...
#quarto #slidecrafing
Updated a Shiny app for learning about outlier statistics for detecting random and (now) patterned responses. Has LazR from Biemann et al (2025) and Autocorrelation from responsePatterns R package for patterned responses.
falkcarl.shinyapps.io/BotApp1/
#rstats #rshiny #DataQuality #SurveyResearch
falkcarl.shinyapps.io/BotApp1/
#rstats #rshiny #DataQuality #SurveyResearch
May 27, 2026 at 3:23 PM
Updated a Shiny app for learning about outlier statistics for detecting random and (now) patterned responses. Has LazR from Biemann et al (2025) and Autocorrelation from responsePatterns R package for patterned responses.
falkcarl.shinyapps.io/BotApp1/
#rstats #rshiny #DataQuality #SurveyResearch
falkcarl.shinyapps.io/BotApp1/
#rstats #rshiny #DataQuality #SurveyResearch
Reposted by Carl F. Falk
What if you dropped a bowling ball in the Mariana Trench?
Watch the latest What If? video in collaboration with
@minuteearth.bsky.social!
www.youtube.com/watch?v=FYoH...
Watch the latest What If? video in collaboration with
@minuteearth.bsky.social!
www.youtube.com/watch?v=FYoH...
What if you dropped a bowling ball in the Mariana Trench?
YouTube video by xkcd's What If?
www.youtube.com
May 26, 2026 at 9:31 PM
What if you dropped a bowling ball in the Mariana Trench?
Watch the latest What If? video in collaboration with
@minuteearth.bsky.social!
www.youtube.com/watch?v=FYoH...
Watch the latest What If? video in collaboration with
@minuteearth.bsky.social!
www.youtube.com/watch?v=FYoH...
Reposted by Carl F. Falk
The new blimp / rblimp is SO much faster for those who are considering giving it a try! #rstats
www.appliedmissingdata.com/blimp
www.appliedmissingdata.com/blimp
Blimp
Blimp 3 offers powerful latent variable modeling and missing data imputation for data sets with up to three levels.
www.appliedmissingdata.com
May 26, 2026 at 11:28 PM
The new blimp / rblimp is SO much faster for those who are considering giving it a try! #rstats
www.appliedmissingdata.com/blimp
www.appliedmissingdata.com/blimp
Reposted by Carl F. Falk
More details about the Bayesian Workflow book and case studies now available on the book web site avehtari.github.io/Bayesian-Wor... (but you still need to wait a bit for the book)
April 7, 2026 at 5:49 PM
More details about the Bayesian Workflow book and case studies now available on the book web site avehtari.github.io/Bayesian-Wor... (but you still need to wait a bit for the book)
Anyone know of an #rstats package that can generate nonnormal data with a specified skewness and kurtosis that's also available was a #wasm binary (i.e., for use with #webr or #shinylive)? quadprog is a dependency of everything I'm aware of. If not, guess I'm just coding something.
May 19, 2026 at 10:13 PM
Anyone know of an #rstats package that can generate nonnormal data with a specified skewness and kurtosis that's also available was a #wasm binary (i.e., for use with #webr or #shinylive)? quadprog is a dependency of everything I'm aware of. If not, guess I'm just coding something.
Paper from Sean Devine, Ken Fujimoto & I: psyarxiv.com/p2n8a/
In extensive simulations, we evaluate model selection using DIC, WAIC, and LOO-CV with marginal and conditional likelihood for Bayesian linear multilevel models.
Happy to hear journal recommendations & feedback!👍
#brms #rstats #bayes
In extensive simulations, we evaluate model selection using DIC, WAIC, and LOO-CV with marginal and conditional likelihood for Bayesian linear multilevel models.
Happy to hear journal recommendations & feedback!👍
#brms #rstats #bayes
OSF
psyarxiv.com
May 14, 2026 at 1:04 PM
Paper from Sean Devine, Ken Fujimoto & I: psyarxiv.com/p2n8a/
In extensive simulations, we evaluate model selection using DIC, WAIC, and LOO-CV with marginal and conditional likelihood for Bayesian linear multilevel models.
Happy to hear journal recommendations & feedback!👍
#brms #rstats #bayes
In extensive simulations, we evaluate model selection using DIC, WAIC, and LOO-CV with marginal and conditional likelihood for Bayesian linear multilevel models.
Happy to hear journal recommendations & feedback!👍
#brms #rstats #bayes
Reposted by Carl F. Falk
I have blocked exactly one person from a project on GitHub. Strong contender for #2 today: a Posit Senior SWE who pointed Claude at my portable-r-macos / portable-r-windows scripts, opened a PR, and linked my work as "existing art."
That's not reference. That's laundering.
Worse no signing on mac.
That's not reference. That's laundering.
Worse no signing on mac.
May 3, 2026 at 8:32 PM
I have blocked exactly one person from a project on GitHub. Strong contender for #2 today: a Posit Senior SWE who pointed Claude at my portable-r-macos / portable-r-windows scripts, opened a PR, and linked my work as "existing art."
That's not reference. That's laundering.
Worse no signing on mac.
That's not reference. That's laundering.
Worse no signing on mac.
Just curious if anyone has ever tried shinylive at the same time as webexercises and whether the two play nicely with each other?
#rstats
#rshiny
#shinylive
#rstats
#rshiny
#shinylive
February 20, 2026 at 3:40 PM
Just curious if anyone has ever tried shinylive at the same time as webexercises and whether the two play nicely with each other?
#rstats
#rshiny
#shinylive
#rstats
#rshiny
#shinylive
While teaching a course on Item Response Theory this semester, I created a Shiny app for visualizing some polytomous item response models: falkcarl.shinyapps.io/polytomous/
This is an initial draft, so comments/questions/suggestions are welcome!
#Psychometrics #RShiny #IRT
This is an initial draft, so comments/questions/suggestions are welcome!
#Psychometrics #RShiny #IRT
December 10, 2025 at 3:31 PM
While teaching a course on Item Response Theory this semester, I created a Shiny app for visualizing some polytomous item response models: falkcarl.shinyapps.io/polytomous/
This is an initial draft, so comments/questions/suggestions are welcome!
#Psychometrics #RShiny #IRT
This is an initial draft, so comments/questions/suggestions are welcome!
#Psychometrics #RShiny #IRT
Reposted by Carl F. Falk
Now I'm also looking for a research software engineer to implement a pile of research results to R packages loo, posterior, bayesplot, projpred, priorsense, brms or/and Python packages ArviZ, Bambi and Kulprit. Apply by email with no specific deadline (see contact info at users.aalto.fi/~ave/)
I'm now also looking for a postdoc with strong Bayesian background and interest in developing Bayesian cross-validation theory, methods and software. Apply by email with no specific deadline (see contact information at users.aalto.fi/~ave/).
Others, please share
Others, please share
I'm looking for a doctoral student with Bayesian background to work on Bayesian workflow and cross-validation (see my publication list users.aalto.fi/~ave/publica... for my recent work) at Aalto University.
Apply through the ELLIS PhD program (dl October 31) ellis.eu/news/ellis-p...
Apply through the ELLIS PhD program (dl October 31) ellis.eu/news/ellis-p...
November 3, 2025 at 11:13 AM
Now I'm also looking for a research software engineer to implement a pile of research results to R packages loo, posterior, bayesplot, projpred, priorsense, brms or/and Python packages ArviZ, Bambi and Kulprit. Apply by email with no specific deadline (see contact info at users.aalto.fi/~ave/)
FYI.
The House of Commons committee where this went down also records the meetings: www.ourcommons.ca/Committees/e...
The House of Commons committee where this went down also records the meetings: www.ourcommons.ca/Committees/e...
November 2, 2025 at 12:53 AM
FYI.
The House of Commons committee where this went down also records the meetings: www.ourcommons.ca/Committees/e...
The House of Commons committee where this went down also records the meetings: www.ourcommons.ca/Committees/e...
Reposted by Carl F. Falk
I'm now also looking for a postdoc with strong Bayesian background and interest in developing Bayesian cross-validation theory, methods and software. Apply by email with no specific deadline (see contact information at users.aalto.fi/~ave/).
Others, please share
Others, please share
I'm looking for a doctoral student with Bayesian background to work on Bayesian workflow and cross-validation (see my publication list users.aalto.fi/~ave/publica... for my recent work) at Aalto University.
Apply through the ELLIS PhD program (dl October 31) ellis.eu/news/ellis-p...
Apply through the ELLIS PhD program (dl October 31) ellis.eu/news/ellis-p...
ELLIS PhD Program: Call for Applications 2025
The ELLIS mission is to create a diverse European network that promotes research excellence and advances breakthroughs in AI, as well as a pan-European PhD program to educate the next generation of AI...
ellis.eu
October 29, 2025 at 2:37 PM
I'm now also looking for a postdoc with strong Bayesian background and interest in developing Bayesian cross-validation theory, methods and software. Apply by email with no specific deadline (see contact information at users.aalto.fi/~ave/).
Others, please share
Others, please share
Reposted by Carl F. Falk
When there is a random way to do something, there is a less random way that is better but requires more thought. In this case, regression models that make no sense don't belong in a multiverse analysis. An inferential regression without a causal justification is like an opinion without reasons.
October 23, 2025 at 4:34 PM
When there is a random way to do something, there is a less random way that is better but requires more thought. In this case, regression models that make no sense don't belong in a multiverse analysis. An inferential regression without a causal justification is like an opinion without reasons.
Anyone else using #shinylive with #rstats having trouble getting nice plotting packages like #ggplot2 or #plotly to work? Curious what work arounds there are. Many thanks! ( #shiny works fine)
October 22, 2025 at 10:39 PM
Anyone else using #shinylive with #rstats having trouble getting nice plotting packages like #ggplot2 or #plotly to work? Curious what work arounds there are. Many thanks! ( #shiny works fine)
Reposted by Carl F. Falk
Join us as we explore our options, tomorrow….
October 20, 2025 at 12:52 PM
Join us as we explore our options, tomorrow….
Reposted by Carl F. Falk
There is still time to submit a proposal to host IMPS 2028! Visit www.psychometricsociety.org/hosting-oppo... for details. #QuantitativePsychology #Psychometrics
October 16, 2025 at 1:52 PM
There is still time to submit a proposal to host IMPS 2028! Visit www.psychometricsociety.org/hosting-oppo... for details. #QuantitativePsychology #Psychometrics
Reposted by Carl F. Falk
I clearly had a lot of thoughts/feelings from reading Terry's blog post, so I wrote one of my own
It ended up being a bit of a stream-of-thought post but I think it captures some of my worries
benharrap.com/post/2025-10...
#statssky #episky #academicsky
It ended up being a bit of a stream-of-thought post but I think it captures some of my worries
benharrap.com/post/2025-10...
#statssky #episky #academicsky
October 10, 2025 at 1:05 AM
I clearly had a lot of thoughts/feelings from reading Terry's blog post, so I wrote one of my own
It ended up being a bit of a stream-of-thought post but I think it captures some of my worries
benharrap.com/post/2025-10...
#statssky #episky #academicsky
It ended up being a bit of a stream-of-thought post but I think it captures some of my worries
benharrap.com/post/2025-10...
#statssky #episky #academicsky
Would sure be funny to embed certain keyword combinations into assignments to mess with cheating students who then copy the questions into an LLM prompt.
October 10, 2025 at 1:44 AM
Would sure be funny to embed certain keyword combinations into assignments to mess with cheating students who then copy the questions into an LLM prompt.